A new routine experiment referred to as buoyancy analysis is proposed to determine the grain-size distribution of fine-grained soils. The buoyancy analysis is based on the sedimentation principles of the hydrometer and pipette analyses. It determines the percent by weight finer than a given grain size by measuring the buoyant weight of a 2.5-cm-diameter sphere immersed in the soil suspension. The buoyancy analysis is slightly more accurate than the hydrometer analysis, has a shorter duration, and its readings can be fed directly into a computer. It yields results identical to those of the hydrometer analysis when the sphere is immersed within the depth range of the hydrometer bulb.

Author Information:

Bardet, J-P Professor and research assistant, University of Southern California, Los Angeles, CA

Young, J Professor and research assistant, University of Southern California, Los Angeles, CA